10/11/23 - How to Pay Lip Service to Density Pt. 2

A standard 40'x100' city lot.

The buildable area of a standard 40' x 100' city lot.

A 1280sf 2-story single family home with driveway on a standard 40' x 100' city lot.

Let's walk through an example of what we can do with a Medium Density Residential (MDR) zoned lot in the city. A few assumptions to get out of the way:

The first three diagrams above represent the lot, the buildable area on the lot, and what a modest, 2 story 1280sf single family house on the lot would look like with the necessary minimum parking. We've chosen dimensions to minimize construction costs for our project, rather than optimizing along any other vectors (such as coverage or square footage or parking). Quick math says that we're covering 1340sf of a 4000sf lot, which is well under the maximum coverage of 2000sf that we're allowed. As you can see, we're cleanly in the buildable area.

A 1920sf duplex with a driveway and parking on a standard 40' x 100' city lot.

A 2304sf three family with a driveway and parking on a standard 40' x 100' city lot.

A 1920sf four family with a driveway and parking on a standard 40' x 100' city lot.

Here's where things get exciting. Our first diagram shows a duplex. Each of the units is 960sf across 2 stories. We have the necessary 2 parking spaces, and we come in at 1924sf covered out of an allowed 2000sf. Already more of the lot is used to accommodate personal motor vehicles than where people live.

Our second diagram is a three family. We've shaved a little off the driveway to make this all fit, but we have 3 units, each 768sf. We're allowed more coverage now, at 60%, or 2400sf total. This design covers 2358sf. We again dedicate more of the lot to parking than to housing.

I'll confess, I didn't think I'd actually be able to put 4 units and 4 parking spaces on a single city sized lot, but I went and proved myself wrong. Here we have 4 480sf units and the 4 parking spaces they need. I'm not sure how we fit kitchens and bathrooms and such into these units, but where there's a will there's a way. We now dedicate twice as much of the lot to parking as we do to people, and that checks, considering the basic outline of each unit is barely larger than a parking space.

I want to pivot a little bit to discussing some other, more expensive options. First, because MDR allows for 35' of height, it would be possible for any of these designs to add a third story in the classic Trinity house (band-box) style from Philadelphia. Unfortunately, in New York, this will require sprinklers, and will add significant cost to the building. The same is true of 3 story townhouses with tuck under parking. Configuring these units as apartments would both require sprinklers and lose interior space to circulation, making it less efficient and more expensive still. For all configurations it might be possible to eke out a few additional square feet by replacing some to all of the driveway and parking areas with permeable pavement solutions. This reduces the calculated coverage of the paved areas by half, and would allow for more building area. It would be significantly more cost for marginal gains though, especially in the case of the four family configuration.

In any event, I'm struggling to believe that a three or four family building would ever be constructed on a standard MDR lot with the rules as they exist. I'd love to be proven wrong, though.

Join us next time in part 3, when I propose the obvious to encourage the density and housing options the ZAP purports to allow and 2034 plan desires.